The primary deowogicaw difference between de two communions is de differing Christowogy. Orientaw Ordodoxy rejects de Chawcedonian Definition, and instead adopts de Miaphysite formuwa, bewieving dat de human and divine natures of Christ are united. Historicawwy, de earwy prewates of de Orientaw Ordodox churches dought dat de Chawcedonian Definition impwied a possibwe repudiation of de Trinity or a concession to Nestorianism.

Oder differences incwude minor deviations in sociaw teaching and different views on ecumenism. Orientaw Ordodox churches are generawwy considered to be more conservative wif regard to sociaw issues as weww more endusiastic about ecumenicaw rewations wif non-Ordodox churches.

The break in communion between de Imperiaw Roman and Orientaw Ordodox churches did not occur suddenwy, but rader graduawwy over 2-3 centuries fowwowing de Counciw of Chawcedon, uh-hah-hah-hah.[9] Eventuawwy de two communions devewoped separate institutions, and de Orientaw Ordodox did not participate in any of de water ecumenicaw counciws.

The Orientaw Ordodox churches maintain deir own ancient apostowic succession, uh-hah-hah-hah.[10] The various churches are governed by howy synods, wif a primus inter pares bishop serving as primate. The primates howd titwes wike patriarch, cadowicos, and pope. Among dese patriarchs, de Pope of Awexandria takes precedence, and is sometimes considered de "face" of Orientaw Ordodoxy. The Awexandrian Patriarchate, awong wif Rome and Antioch, was one of de most prominent sees of de earwy Christian Church, and contains a majority popuwation of Coptic Christians, and unwike Antioch is stiww a major popuwation center.

That said, de Pope of Awexandria has no governing powers wif respect to de non-Coptic churches. Orientaw Ordodoxy does not have a magisteriaw weader wike de Roman Cadowic Church, nor does de communion have a weader who can convene ecumenicaw synods wike de Eastern Ordodox Church.

The schism between Orientaw Ordodoxy and de adherents of Chawcedonian Christianity was based on differences in Christowogy. The First Counciw of Nicaea, in 325, decwared dat Jesus Christ is God, dat is to say, "consubstantiaw" wif de Fader. Later, de dird ecumenicaw counciw, de Counciw of Ephesus, decwared dat Jesus Christ, dough divine as weww as human, is onwy one being, or person (hypostasis). Thus, de Counciw of Ephesus expwicitwy rejected Nestorianism, de Christowogicaw doctrine dat Christ was two distinct beings, one divine (de Logos) and one human (Jesus), who happened to inhabit de same body. The churches dat water became Orientaw Ordodoxy were firmwy anti-Nestorian, and derefore strongwy supported de decisions made at Ephesus.

Twenty years after Ephesus, de Counciw of Chawcedon reaffirmed de view dat Jesus Christ was a singwe person, but at de same time decwared dat dis one person existed "in two compwete natures", one human and one divine. Those who opposed Chawcedon saw dis as a concession to Nestorianism, or even as a conspiracy to convert de Church to Nestorianism by steawf. As a resuwt, over de fowwowing decades, dey graduawwy separated from communion wif dose who accepted de Counciw of Chawcedon, and formed de body dat is today cawwed Orientaw Ordodoxy.

At times, Chawcedonian Christians have referred to de Orientaw Ordodox as being Monophysites–dat is to say, accusing dem of fowwowing de teachings of Eutyches (c. 380 – c. 456), who argued dat Jesus Christ was not human at aww, but onwy divine. Monophysitism was condemned as hereticaw awongside Nestorianism, and to accuse a church of being Monophysite is to accuse it of fawwing into de opposite extreme from Nestorianism. However, de Orientaw Ordodox demsewves reject dis description as inaccurate, having officiawwy condemned de teachings of bof Nestorius and Eutyches. They define demsewves as Miaphysite instead, howding dat Christ has one nature, but dis nature is bof human and divine.[11]

Today, de Orientaw Ordodox churches are in fuww communion wif each oder, but not wif de Eastern Ordodox Church or any oder churches. Swow diawogue towards restoring communion between de two Ordodox groups began in de mid-20f century,[12] and diawogue is awso underway between Orientaw Ordodoxy and de Cadowic Church and oders.[13] In 2017, de mutuaw recognition of baptism was restored between de Coptic Ordodox Church of Awexandria and de Cadowic Church.[14] Awso baptism is mutuawwy recognized between de Armenian Apostowic Church and de Cadowic Church.[15][16]

The schism between de Orientaw Ordodox and de rest of Christendom occurred in de 5f century. The separation resuwted in part from de refusaw of Pope Dioscorus I of Awexandria and de oder dirteen Egyptian bishops to accept de Christowogicaw dogmas promuwgated by de Counciw of Chawcedon, which hewd dat Jesus is in two natures: one divine and one human, uh-hah-hah-hah. They wouwd accept onwy "of or from two natures" but not "in two natures".

To de hierarchs who wouwd wead de Orientaw Ordodox, de watter phrase was tantamount to accepting Nestorianism, which expressed itsewf in a terminowogy incompatibwe wif deir understanding of Christowogy. Nestorianism was understood as seeing Christ in two separate natures, human and divine, each wif different actions and experiences; in contrast Cyriw of Awexandria advocated de formuwa "One Nature of God de Incarnate Logos"[17] (or as oders transwate,[18] "One Incarnate Nature of de Word"), stressing de unity of de incarnation over aww oder considerations. It is not entirewy cwear dat Nestorius himsewf was a Nestorian, uh-hah-hah-hah.

Christowogy, awdough important, was not de onwy reason for de Awexandrian Church's refusaw to accept de decwarations of de Counciw of Chawcedon; powiticaw, eccwesiasticaw and imperiaw issues were hotwy debated during dat period.

In de years fowwowing Chawcedon de patriarchs of Constantinopwe intermittentwy remained in communion wif de non-Chawcedonian Patriarchs of Awexandria and Antioch (see Henotikon), whiwe Rome remained out of communion wif de watter and in unstabwe communion wif Constantinopwe. It was not untiw 518 dat de new Byzantine Emperor, Justin I (who accepted Chawcedon), demanded dat de Church in de Roman Empire accept de Counciw's decisions.[19]

Justin ordered de repwacement of aww non-Chawcedonian bishops, incwuding de patriarchs of Antioch and Awexandria. The extent of de infwuence of de Bishop of Rome in dis demand has been a matter of debate. Justinian I awso attempted to bring dose monks who stiww rejected de decision of de Counciw of Chawcedon into communion wif de greater church. The exact time of dis event is unknown, but it is bewieved to have been between 535 and 548.

St Abraham of Farshut was summoned to Constantinopwe and he chose to bring wif him four monks. Upon arrivaw, Justinian summoned dem and informed dem dat dey wouwd eider accept de decision of de Counciw or wose deir positions. Abraham refused to entertain de idea. Theodora tried to persuade Justinian to change his mind, seemingwy to no avaiw. Abraham himsewf stated in a wetter to his monks dat he preferred to remain in exiwe rader dan subscribe to a faif which he bewieved to be contrary to dat of Adanasius of Awexandria.

By de 20f century de Chawcedonian schism was not seen wif de same importance, and from severaw meetings between de audorities of de Howy See and de Orientaw Ordodoxy, reconciwing decwarations emerged in de common statement of Syriac Patriarch Mar Ignatius Zakka I Iwas and de Roman Pope John Pauw II in 1984:

The confusions and schisms dat occurred between deir Churches in de water centuries, dey reawize today, in no way affect or touch de substance of deir faif, since dese arose onwy because of differences in terminowogy and cuwture and in de various formuwae adopted by different deowogicaw schoows to express de same matter. Accordingwy, we find today no reaw basis for de sad divisions and schisms dat subseqwentwy arose between us concerning de doctrine of Incarnation, uh-hah-hah-hah. In words and wife we confess de true doctrine concerning Christ our Lord, notwidstanding de differences in interpretation of such a doctrine which arose at de time of de Counciw of Chawcedon, uh-hah-hah-hah.[20]

According to de canons of de Orientaw Ordodox churches, de four bishops of Rome, Constantinopwe, Awexandria and Antioch were aww given status as patriarchs; in oder words, de ancient apostowic centres of Christianity, by de First Counciw of Nicaea (predating de schism)—each of de four patriarchs was responsibwe for dose bishops and churches widin his own area of de Church. Thus, de Bishop of Rome has awways been hewd by de oders to be fuwwy sovereign widin his own area, as weww as "first-among-eqwaws", due to de traditionaw bewief dat de ApostwesSaint Peter and Saint Pauw were martyred in Rome.[citation needed]

The technicaw reason for de schism was dat de bishops of Rome and Constantinopwe excommunicated de non-Chawcedonian bishops in 451 for refusing to accept de "in two natures" teaching, dus decwaring dem to be out of communion, uh-hah-hah-hah.

The highest office in Orientaw Ordodoxy is dat of patriarch. There are patriarchs widin de wocaw Orientaw Ordodox communities of de Coptic, Armenian, Eritrean, Ediopian, Syriac, and Indian (Mawankara) Ordodox churches. The titwe of pope, as used by de weading bishop of de Coptic Church, has de meaning of "Fader" and is not a jurisdictionaw titwe.

It is a minority in Egypt (<20%),[25]Sudan (3–5%),[citation needed]Syria (2–3% out of de 10% of totaw Christians), Lebanon (10% of de 40% of Christians in Lebanon or 200,000 Armenians and members of de Church of de East) and Kerawa, India (7% out of de 20% of totaw Christians in Kerawa).[26] In terms of totaw number of members, de Ediopian Church is de wargest of aww Orientaw Ordodox churches, and is second among aww Ordodox churches among Eastern and OrientawcChurches (exceeded in number onwy by de Russian Ordodox Church).

There are a number of churches considered non-canonicaw, but whose members and cwergy may or may not be in communion wif de greater Orientaw Ordodox communion, uh-hah-hah-hah. Exampwes incwude de Cewtic Ordodox Church, de Ancient British Church, and watewy de British Ordodox Church. These organizations have passed in and out of officiaw recognition, but members rarewy face excommunication when recognition is ended. The primates of dese churches are typicawwy referred to as episcopi vagantes or vagantes in short.

The division between de two sees intensified during de Soviet period. By some Western bishops and cwergy de Howy See of Etchmiadzin was seen as a captive Communist puppet. Sympadizers of dis estabwished congregations independent of Etchmiadzin, decwaring woyawty instead to de See based in Antewias in Lebanon. The division was formawized in 1956 when de Antewias (Ciwician) See broke away from de Etchmiadzin See. Though recognising de supremacy of de Cadowicos of Aww Armenians, de Cadowicos of Ciwicia administers de cwergy and dioceses independentwy. The dispute, however, has not at aww caused a breach in communion between de two churches.

In 1992, fowwowing de abdication of Abune Merkorios and ewection of Abune Pauwos, some Ediopian Ordodox bishops in de United States maintained dat de new ewection was invawid, and decwared deir independence from de Addis Ababa administration, uh-hah-hah-hah.[29]

The Assyrian Church of de East is sometimes incorrectwy described as an Orientaw Ordodox church, dough its origins wie in disputes dat predated de Counciw of Chawcedon and it fowwows a different Christowogy from Orientaw Ordodoxy. The historicaw Church of de East was de church of Greater Iran and decwared itsewf separate from de state church of de Roman Empire in 424–27, years before Chawcedon, uh-hah-hah-hah. Theowogicawwy, de Church of de East was affiwiated wif de doctrine of Nestorianism, and dus rejected de Counciw of Ephesus, which decwared Nestorianism hereticaw in 431. The Christowogy of de Orientaw Ordodox churches in fact devewoped as a reaction against Nestorian Christowogy, which emphasizes de distinctness of de human and divine natures of Christ.